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<head><meta charset="utf-8"><title>build change in src/llvm_project · t-compiler · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/index.html">t-compiler</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html">build change in src/llvm_project</a></h3>

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<a name="221228998"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221228998" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> devsnek <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221228998">(Dec 30 2020 at 17:17)</a>:</h4>
<p>how do i tell x.py to try to build llvm again, without completely wiping the llvm output? i just made a quick one-line change to test something and i'd like to not rebuild llvm from scratch if possible <span aria-label="sweat smile" class="emoji emoji-1f605" role="img" title="sweat smile">:sweat_smile:</span></p>



<a name="221229088"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221229088" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221229088">(Dec 30 2020 at 17:18)</a>:</h4>
<p>if you just run <code>x.py build</code> it shouldn't build from scratch I don't think</p>



<a name="221229102"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221229102" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221229102">(Dec 30 2020 at 17:18)</a>:</h4>
<p>(also this should probably have gone in <a class="stream" data-stream-id="182449" href="/#narrow/stream/182449-t-compiler.2Fhelp">#t-compiler/help</a> but nbd)</p>



<a name="221229165"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221229165" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> devsnek <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221229165">(Dec 30 2020 at 17:19)</a>:</h4>
<p>it doesn't even check if llvm needs to be rebuilt, i assume there's a buildstamp somewhere but idk...</p>



<a name="221229205"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221229205" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221229205">(Dec 30 2020 at 17:20)</a>:</h4>
<p>oh I see - try <code>fd .llvm-stamp build/</code> and see if that comes up with anything</p>



<a name="221229395"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221229395" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> devsnek <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221229395">(Dec 30 2020 at 17:22)</a>:</h4>
<p>yeah can't find anything... tried grepping around for files named <code>*stamp*</code>.</p>



<a name="221229403"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221229403" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221229403">(Dec 30 2020 at 17:22)</a>:</h4>
<p>I _think_ it's llvm-finished-building in build/$triple/llvm</p>



<a name="221229414"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221229414" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221229414">(Dec 30 2020 at 17:22)</a>:</h4>
<p>for me it's in <code>build/x86_64-unknown-linux-gnu/ci-llvm/.llvm-stamp</code></p>



<a name="221229422"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221229422" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221229422">(Dec 30 2020 at 17:22)</a>:</h4>
<p>you need a <code>-uu</code> flag to fd, sorry</p>



<a name="221229522"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221229522" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> devsnek <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221229522">(Dec 30 2020 at 17:24)</a>:</h4>
<p>don't have a <code>ci-llvm</code> dir. maybe one of these?</p>
<div class="codehilite"><pre><span></span><code>build/x86_64-unknown-linux-gnu/stage0-rustc/release/.fingerprint/rustc_llvm-c0888cab6cee53aa/invoked.timestamp
build/x86_64-unknown-linux-gnu/stage0-rustc/release/.fingerprint/rustc_llvm-1d34e08153049cb0/invoked.timestamp
build/x86_64-unknown-linux-gnu/stage0-rustc/x86_64-unknown-linux-gnu/release/.fingerprint/rustc_codegen_llvm-fcbb9e3cca21d87e/invoked.timestamp
build/x86_64-unknown-linux-gnu/stage0-rustc/x86_64-unknown-linux-gnu/release/.fingerprint/rustc_codegen_llvm-b79fa8cdbda8d7a1/invoked.timestamp
build/x86_64-unknown-linux-gnu/stage0-rustc/x86_64-unknown-linux-gnu/release/.fingerprint/rustc_llvm-61cff5404d82060d/invoked.timestamp
build/x86_64-unknown-linux-gnu/stage0-rustc/x86_64-unknown-linux-gnu/release/.fingerprint/rustc_llvm-df546587a75aa713/invoked.timestamp
build/x86_64-unknown-linux-gnu/stage0-rustc/x86_64-unknown-linux-gnu/release/build/rustc_llvm-e7ac7d054fce0b79/invoked.timestamp
build/x86_64-unknown-linux-gnu/stage0-rustc/x86_64-unknown-linux-gnu/release/build/rustc_llvm-a888d257b333c181/invoked.timestamp
</code></pre></div>



<a name="221229593"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221229593" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Joshua Nelson <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221229593">(Dec 30 2020 at 17:24)</a>:</h4>
<p>hmm those are for the rustc_llvm crate I think</p>



<a name="221229890"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221229890" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> devsnek <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221229890">(Dec 30 2020 at 17:28)</a>:</h4>
<p>whelp i tried deleting <code>build/x86_64-unknown-linux-gnu/llvm/llvm-finished-building</code> but it looks like it is building from scratch now. oh well</p>



<a name="221229913"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221229913" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> devsnek <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221229913">(Dec 30 2020 at 17:28)</a>:</h4>
<p>time to go do something else for an hour <span aria-label="smile cat" class="emoji emoji-1f638" role="img" title="smile cat">:smile_cat:</span></p>



<a name="221229968"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221229968" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221229968">(Dec 30 2020 at 17:30)</a>:</h4>
<p>there's some amount of luck involved <span aria-label="sob" class="emoji emoji-1f62d" role="img" title="sob">:sob:</span></p>



<a name="221230101"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221230101" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> lqd <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221230101">(Dec 30 2020 at 17:31)</a>:</h4>
<p>that is, I'm pretty sure I've seen this file mentioned with the word "luck" in the same sentence</p>



<a name="221232403"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221232403" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> devsnek <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221232403">(Dec 30 2020 at 18:02)</a>:</h4>
<p>so after rebuilding llvm, the change doesn't even show up -&gt; <a href="https://gc.gy/77056334.png">https://gc.gy/77056334.png</a></p>
<div class="message_inline_image"><a href="https://gc.gy/77056334.png"><img src="https://gc.gy/77056334.png"></a></div>



<a name="221235775"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221235775" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221235775">(Dec 30 2020 at 18:48)</a>:</h4>
<p>make sure you commit your llvm change</p>



<a name="221235794"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221235794" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221235794">(Dec 30 2020 at 18:49)</a>:</h4>
<p>x.py will <code>checkout -f</code> the submodule by default, at least used to in the past.</p>



<a name="221235931"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221235931" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221235931">(Dec 30 2020 at 18:50)</a>:</h4>
<p>or something along those lines anyway – I just remember having trouble having my changes be built back when I hacked on llvm within rustc last time.</p>



<a name="221238113"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221238113" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Alessandro Decina <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221238113">(Dec 30 2020 at 19:13)</a>:</h4>
<p><span class="user-mention" data-user-id="219805">@devsnek</span> if you're hacking on llvm within rustc, I highly recommend enabling ccache for it, it reliably brings build times down to seconds after the first build</p>



<a name="221238313"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221238313" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Alessandro Decina <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221238313">(Dec 30 2020 at 19:15)</a>:</h4>
<p><span class="user-mention silent" data-user-id="123586">nagisa</span> <a href="#narrow/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project/near/221235775">said</a>:</p>
<blockquote>
<p>make sure you commit your llvm change</p>
</blockquote>
<p>I think it might be the opposite: if you commit but don't update the submodule, it will checkout the commit referenced in the submodule. If you don't commit it should work</p>



<a name="221239905"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/131828-t-compiler/topic/build%20change%20in%20src/llvm_project/near/221239905" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nagisa <a href="https://rust-lang.github.io/zulip_archive/stream/131828-t-compiler/topic/build.20change.20in.20src.2Fllvm_project.html#221239905">(Dec 30 2020 at 19:33)</a>:</h4>
<p>Ah right that might have been the case.</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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